Rectifying radio shield



' Sept. s, 1927'.

1,641,395 T. MOORE RECTIFYING RADIO SHIELD Filed Sept. 15. 1924 ggmovvawPatented Sept. 6, 1927.

UNITED STATES PATENT OFFICE.

[from moons. or cnvcrm'uri, onro.

nnorrrme nnmo SHIELD.

Application filed September 15, 1924. Serial No. 787,670.

In the building and operation of radio apparatus it has been foundadvantageous to.

provide metallic shields suitably grounded for collectin and removingstray currents which may e given off by various parts of the ap aratusand for neutralizing the so called ody capacity of the operator of theapparatus.

An ob'ect of my invention is to provlde a radio s ield which is simpleand inexpensive to manufacture and which may be applied to various useswith a minimum of effort.

Another object is to rovide a shield of this character which wi lrectify stray currents and consequently cause them to be carried to aground wire with greater rapidity than the present knownmetallicshields.

Another object of my invention is to provide a device of this kind whichis flexible and has greater adaptability to its applica-' tion to radioapparatus. 7

These and other objects are attained by the means described herein anddisclosed in the accompanying drawings, in which:

Fig. 1 is a fragmental plan view of a radio receiving apparatus havingshields of my invention embodied therein.

- relative positions 0 Fig. 2 is a fragmental view of a shield of myinvention showin diagrammatically the its component parts.'. The shield3 comprises a base 4 which ma V be of any suitable material such as carboard, fibre, fish pa r or the like, such base being preferably thln andflexible. The base 4 is itself a dielectric and has a dielectric boating5 on its one side. The dielectric may be of any suitable material but isreferably one which may be applied in solutlon such as shellac, waterglass, or any suitable dielectric varnish. A conducting material 6 in avery.

thin sheet form is next placed over the dielectric subs'tance and issecured thereto by the natural adhesion of the dielectric solution. Theconductormaterial 6 may be tin foil or similar material but ispreferably 'formed of a foil composed of an alloy of one-half block tinand one-half lead. A la er of borax 7 or other suitable salts of li echemical properties in the form of a solution is next applied over theconductor substance, water or alcohol or an other suitable fluid beingused to keep t e borax in a solution form for'easily applying the sameover the conductor. Next there 13 applied over the borax a quantity ofaluminum 8 in thus eliminate vibration. Due to. the

sheet owdered or flour form. The material thus ormed is allowed to standuntil the chemical action of the borax and metals has ceased after whichthe sheet is hardened and unified by means of heat and pressure ap-.plied in any suitable manner. The structure .thus formed is veryflexible and tough but may be cut or drilled with an ordinary pocketknife and is thus very easily workedin applying it to its uses.

When it is desired to apply the rectifying shield 3 of my invention forexample to the inside of the dielectric panel 9 of a radio receivingapparatus 10, a sheet of the shielding material is cut and erforated toaccommodate the apparatus an instruments that may be applied to thepanel by means of glue or shellac or in any other manner that may bechosen by the radio builder. The metallic side of the shield iselectrically connected with the ground connection 11 offthe radioapparatus as is common in connecting the ordinary .electric shield.

WVhen' it is desired to place a shield between two instruments of areceiving set for example 13 and 14, the shield of my invention has beenfound to overcome one of the difiiculties previously experienced withplain metallic'shields. Two of the instruments 13 and 14 for example aregiving ofi electrical energy or stray currents and are each mutuallyaffected by said stray currents emanating from the other instrument. Ifa plain sheet metal shield is used,

these opposed. straycurrents set up vibratlons in the shield which areplainly audible 1n the radio reception. When it is desired to apply theshield of my invention to a ence of the fibre or card-board, anypossible vibrations due to external disturbances will also bedeadenedand rendered inaudible. It will be noted that there has beenpro- ,vided a radio shield which is not only inexpensive of manufactureand ea to a l but which embodies the advantag z of a r e prestifier andthus produces results not attainable by the use of ordinary metallicshields.

What I claim is: 1. As a new article of manufacture a rectifying radioshield in the form of a single sheet.

2.- As a new article of manufacture a bi-' metallic radio shield in theform of a single sheet, the two metallic elements of the shield servingto recti alternating currents and -impulses transmitted thereto whereby0g; posed stray. alternating impulses may carried away withoutdisturbance.

3. Asa new article of manufacture a flexiv ble rectifying radio shield.-1

- 4; In a device of the class-described the combination with a base offibrous material a dielectric, a metallic conductor, a chemical salt andaluminum arranged one upon the having layers of tin foil, borax andaluminum respectively mounted thereon in the order named for forming asingle flexible radio shield.

In testimony whereof, I have hereunto subscribed my name this 12th dayof September, 1924;

TOM MOORE.

